A law enforcement source close to the investigation told the network that, in addition to being refused daily showers, the children of David and Louise Turpin — both suspected of torture and child endangerment — were fed one meal a day.

David, 57, and Louise, 49, will be arraigned on Thursday morning in a California court, where they will have their first opportunity to enter pleas.

PICTURED: Parents David and Louise Turpin were arrested on torture and child endangerment charges after police say they kept their 13 child, ranging from 2 to 29, shackled in their Perris, California home https://t.co/eJDJgQZ6JKpic.twitter.com/ABNxvlY4C9

Police allege that thee 13 Turpin children — ranging in ages from 2 to 29 — were found living in squalor, with some “shackled” to furniture. Malnutrition apparently stunted their growth.

A neighbor at their former home in Murrieta, California, told ABC News he noticed unusual activity coming from the Turpin house.

“I’d come home anywhere from 12:30 to 3 in the morning to see the kids marching [inside the house] in single file for hours,” Mike Clifford said.

The children, he explained, also had some unusual behaviors.

“They talked very monotone and robotic and they talked at the same time, saying the same thing,” Clifford said.

David and Louise Turpin, the Perris, California, parents accused of keeping their 13 children shackled in their home, filed for bankruptcy in 2011. David Turpin was earning $140,000 a year as an engineer at Northrop Grumann. Here's what else we've learned: https://t.co/eJDJgQZ6JKpic.twitter.com/0b6vyKMKy0

Elizabeth Flores, one of Louise Turpin’s estranged sisters, also spoke to ABC News about how strict the couple was with their children.

“They were really strict on the oldest daughter,” Flores said. “She was bound to her room a lot and they would let her come down and eat meals. Before she sat down, she had to get permission and she knew she had to look her mom in the eye and there would be a smile between them and she’d tell her, ‘Go ahead.'”